Over at PANBO, they have done an article about a S. Florida based company, Global Ocean Security Technology (GOST).
I have had small dealings with them in the past, and find them always willing to talk with me. Their product line ranges from security devices for your dinghy up to complete electronic surveillance and tracking packages for megayachts. All the equipment is designed to be used in the maritime, salt water environment – one of the reasons I recommend their products.
If you are serious about protecting your vessel and crew, I highly recommend you visit their site, look them up at the next major boat show in your area, or contact them directly.